<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			function fun(){
				let btn=document.querySelector("button")
				if(btn.innerHTML=="播放"){
					btn.innerHTML="<b>暂停</b>"
				}else{
					btn.innerHTML="播放"
				}
			}
		</script>
	</head>
	<body>
		<button type="button" onclick="fun()">播放</button>
	</body>
</html>
